wiki:UM/MesoscaleModelling

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Mesoscale Modelling

This section provides information specific to the mesoscale weather modelling community.

Mesoscale weather modelling support provides:

  • UM start dumps from the Met Office,
  • Ancillary file creation,
  • Data visualization tools,
  • Analysis tools for diagnostics, such as NDdiag

Getting Initial Data

Start dumps for the UM, lateral boundary condition (LBC) files and ensemble data can be obtained from the Met Office Managed Archive Storage System (MASS). This is accessed using the MOOSE client - see MOOSE User Guide. The data period ranges from 1 January 2006 to the current time. Start dumps from earlier periods can be constructed as GRIB files from ECMWF data.

To get the data, create a help desk ticket and include: the dates and times required, project name, estimate of the data volume in GB, and where in MASS the data is located, if it is not one of the standard sets below.

Getting data from the Met Office

The start dumps are stored in MASS, which can be accessed via MONSooN or JASMIN using the MOOSE interface. Instructions for setting up external access to MASS from JASMIN are available on the Collaboration Twiki. Access via Monsoon is discussed next.

Login to Monsoon (xcs) and use the script get_dump. It takes a single argument which is the date of the required start dump,

   get_dump yyyymmddhh

The structure of the MASS repository has changed over the years due to changes in storage formats and file naming conventions. The script deals with dates from the earliest time 2006/01/01 0Z and works up to 2019/06/26.

Not every date is available as the Met Office had a policy of thinning out the oldest part of the database. In that case get a start dump prior to the time you want and run the UM forecast model to catch up.

For further information on using MOOSE on MONSooN and JASMIN see: Getting started with MOOSE on MONSooN and JASMIN.

UKV Model start dumps

The UKV start dumps use a non-regular, or variable, grid. The UKV start dumps are stored in MASS with path names like,

  • moose:/opfc/atm/ukv/rerun/201108.file/20110810_qwqv03.T+1
  • moose:/opfc/atm/ukv/rerun/201108.file/20110810_qwqv06.T+1

UKV forecasts and analyses

The UKV forecasts and analyses are stored in the MASS with path names like,

moose:/opfc/atm/ukv/prodm/YYYY.pp/prodm_op_ukv_YYYYMMDD_AA_NNN.pp for the multilevel fields and

moose:/opfc/atm/ukv/prods/YYYY.p/prods_op_ukv_YYYYMMDD_AA_NNN.pp

where,

  • YYYY = year e.g. 2011,
  • MM = month e.g. 05,
  • DD = day e.g. 21
  • AA = analysis time = 03, 09, 15 or 21
  • NNN = the part of the forecast - in steps of two from 000 to 036. e.g. 000, 002, 004, …, 036

MOGREPS data

Met Office Global and Regional Ensemble Prediction System (MOGREPS) outputs are also stored in MASS. For background see https://www.metoffice.gov.uk/research/weather/ensemble-forecasting/mogreps.

Ensemble fields are in:

moose:/opfc/atm/mogreps-g/rerun/YYYYMM.file moose:/opfc/atm/mogreps-r/rerun/YYYYMM.file

where YYYY = year e.g. 2011, MM = month e.g. 07.

At minimum, to re-run MOGREPS-R you need the analysis files in the MOGREPS-R path e.g. 20110722_qwqy06.T+0.18km 20110722_qwqy18.T+0.18km, and all the perturbations files e.g. 20110722_perts.qwey06.oper??.pp1 where ?? goes from 00 to 23 members. Also in the MOGREPS-G path, you need the boundary files e.g. 20110722_qweg00.oper??.FRAMES.EY.tar.gz.

Getting data from ECMWF

GRIB format start dumps can be created from ECWMF MARS catalogue data. The GRIB start dumps are created by concatenating the following fields:

  • skin temperature,
  • surface pressure,
  • land-sea mask,
  • geo-potential,
  • temperature,
  • specific humidity,
  • U and V wind velocities

This is the minimum necessary to start the UM.

These fields can be provided from the ERA Interim, ERA5 or other databases. There are a number of scripts available to create these.

The script get-start gets a start dump. It should be run on ECMWF computer ecgate.

The command is,

get_start yyyy mm dd hr

with spaces between the date components. This gets an operational analysis dump.

If your UM model is currently using a Met Office start dump and you need to use a GRIB start dump, you will need to modify your UM model set up. You will need to tell it you are using a GRIB file and also modify the reconfiguration to supply the fields that are missing in the GRIB start dump.

There is also a web interface to the MARS database at https://www.ecmwf.int

External Links

NCAS Climate and High Impact Weather

NCAS Air Quality

Mesoscale Group, University of Reading

W. McGinty

18 July 2019

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